1. Field of the Invention
The present invention relates generally to devices for testing spark plugs used in internal combustion engines, and, more particularly, to a device which permits testing a spark plug that is in present in the electrical circuitry of the internal combustion engine.
2. Description of the Prior Art
The performance of an internal combustion engine depends upon a number of factors, and one major factor is the proper performance of the engine's electrical system. A key component of the electrical system is the spark plug. In conjunction with the spark plug, there are other electrical components that comprise the circuitry that supplies the electrical energy to the spark plug for effecting the spark.
When engine problems develop or when an engine tune up is carried out, it is often important to test the spark plugs to see if they are producing a spark. Throughout the years, a number of innovations have been developed relating to testing spark plugs. One way of testing a spark plug is to disconnect the spark plug from its associated circuitry, to remove the spark plug from the engine, and to test the spark plug on a device that is independent of the engine. A patent disclosing this approach is U.S. Pat. No. 4,156,839. This approach may adequately test the spark plug itself, but it provides no indication as to whether the circuitry on the engine that is supposed to provide electrical energy to the spark plug on the engine is adequately supplying that energy to the spark plug. In this respect, it would be desirable if a spark plug testing device were provided which indicates whether the circuitry that is supposed to supply electrical energy to the spark plug is actually providing energy to the spark plug.
Additional innovations have been developed throughout the years that permit evaluation of a spark plug on the engine as it is connected to the electrical circuitry that energizes the spark plug. The following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 4,291,383; and 4,825,167. Both of these patents have a common characteristic; that is, both of these patents disclose complex electronic testing circuitry and equipment for carrying out the tests. In their complexity, the devices disclosed in both of these patents test and measure a number of electrical properties of the electrical circuitry that go far beyond whether the spark plug is actually sparking while on the engine and connected to its energizing circuitry. In this respect, it would be desirable if a spark plug testing device were provided which does not have complex electrical circuitry. Furthermore, in this respect, it would be desirable if a spark plug testing device were provided which does not test and measure electrical properties that go far beyond simply whether the spark plug is actually sparking while on the engine and connected to its energizing circuitry.
In addition, the following U.S. patents disclose some additional innovations associated with spark plugs or wiring for internal combustion engines: U.S. Pat. No. 3,910,541.; and U.S. Pat. Des. No. 265,381. More specifically, U.S. Pat. No. 3,910,541 discloses a holder for a spare spark plug, wherein the holder is attached to an electrical wire on the engine. U.S. Pat. Des. No. 265,381 discloses a wire clip.
Still other features would be desirable in a spark plug testing apparatus. Rather than using complex electronic testing equipment, it would be desirable if a spark plug testing apparatus permitted the use of the human eye to test for the presence of a spark in the spark plug.
Generally, a spark plug has a round threaded portion that screws into a complementary threaded orifice in the internal combustion engine. There are a number of purposes that the threaded connection between the threaded connections on the spark plug and the engine serve. First, the threaded connection physically supports the spark plug on the engine. Second, the threaded connection provides an gas-tight seal to keep combustion gases from leaking out of the engine cylinder. Third, the threaded connection provides an electrical contact between the spark plug and the engine which is at electrical ground. To test the electrical characteristics of the spark plug in its energizing circuitry, it is important that a good electrical connection be maintained between the spark plug and the engine. In this respect, it would be desirable if a spark plug testing device were provided which maintained a good electrical connection between the spark plug and the engine.
When an engine and a spark plug are cold before running, high temperatures do not prevent a person from handling the spark plug or contacting the engine. However, once the engine has been operating, intense heat builds up very rapidly, especially on spark plugs which are exposed to the internal combustion in the engine. In this respect, it would be desirable if a spark plug testing device were provided which precluded the necessity of a person's hands from directly touching a spark plug that is hot after the engine has been running.
In order to remove or install a spark plug from or to an internal combustion engine, a spark plug socket is usually employed. In this respect, it would be desirable if a spark plug testing device were provided which is combined with a spark plug socket.
To gain leverage for unscrewing and screwing a spark plug out of or into an internal combustion engine, a handle is used with the spark plug socket. In that it would be desirable if the spark plug testing device were combined with a spark plug socket, it would also be desirable if a spark plug testing device were combined with a handle and a spark plug socket.
During a tune up, whether a used spark plug or a new spark plug is installed in the engine, several functions are associated with the spark plug. For example, the proper gap should be set on the spark plug. Also, if the spark plug is a used one, then dirt should be cleaned off of the spark plug, especially in the region of the gap. In this respect, it would be desirable if a spark plug testing device were provided which is combined with devices for measuring the proper gap for the spark plug and for cleaning the spark plug.
Often the spark plug handle and the spark plug socket are disconnected from each other when placed in storage. This is because when the handle and the socket are connected together during use, they form a T-shaped structure which occupies quite a bit of storage space. When they are disassembled for storage, the may be placed side by side to occupy far less storage space. Nevertheless, the separated spark plug socket and the handle may become separated from each other during storage. To keep the spark plug socket, and its associated spark plug testing apparatus, together with the handle during storage, it would be desirable if a connector were provided that connected the spark plug socket with the handle during storage.
A spark plug gap has a relatively small dimension. As such, it may be difficult to readily see with the naked eye. The respective shapes of the two electrodes forming the gap of the spark plug may also be difficult to see with the naked eye. In this respect, it would be desirable if a spark plug testing device were provided which includes a magnifying glass to enable better seeing of the spark plug gap during gapping and cleaning operations.
Thus, while the foregoing body of prior art indicates it to be well known to use devices for testing spark plugs, the prior art described above does not teach or suggest a spark plug testing apparatus which has the following combination of desirable features: (1) indicates whether the circuitry that is supposed to supply electrical energy to the spark plug is actually providing energy to the spark plug; (2) does not have complex electrical circuitry; (3) does not test and measure electrical properties that go far beyond simply whether the spark plug is actually sparking while on the engine and connected to its energizing circuitry; (4) permits the use of the human eye to test for the presence of a spark in the spark plug; (5) maintains a good electrical connection between the spark plug and the engine; (6) precludes the necessity of a person's hands from directly touching a spark plug that is hot after the engine has been running; (7) is combined with a spark plug socket; (8) is combined with a handle and a spark plug socket; (9 ) is combined with devices for measuring the proper gap for the spark plug and for cleaning the spark plug; (10) provides a connector that connects the spark plug socket with the handle during storage; and (11) includes a magnifying glass to enable better seeing of the spark plug gap during gapping and cleaning operations. The foregoing desired characteristics are provided by the unique spark plug testing apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.